Human airway epithelial cell cultures maintained at an air-liquid interface (ALI) recapitulate mucociliary[unreadable] differentiation found in vivo, regulating ion transport, mucin secetion and ciliated cell beating to reproduce[unreadable] mucociliary clearance mechanisms characterisitic of the native human mucosa. These cultures are an[unreadable] excellent model to study the role of CFTR, ENaC, nucleotide/nucleoside regulatory systems and their[unreadable] integrated function in health and disease as proposed in projects 1-4 of the current PPG, respectively. A[unreadable] Tissue Procurement and Cell Culture Core was established at the University of North Carolina in 1984,[unreadable] under the auspices of the CF Foundation, to provide standardized cell cultures to CF researchers. The Core[unreadable] has supported PPG projects since 2000 and has increased its output and capabilities to meet growing[unreadable] research demands. The Core routinely makes available cells and media that are unavailable and/or[unreadable] prohibitively expensive if purchased from commercial suppliers. The purpose of the present application is to[unreadable] provide continuity in the supply of airway specimens and large numbers of human airway epithelial cell[unreadable] cultures to PPG investigators, and to support the use of cultures in mechanistic studies. To accomplish[unreadable] these goals, we propose the following specific functions. 1) Tissue Procurement- Obtain nasal and bronchial[unreadable] tissues from normal, disease control, and CF humans as sources of airway epithelial cells and for acute ex[unreadable] vivo experiments, biochemical studies, in situ hybridization and immunohistochemistry. Characterize donors[unreadable] with respect to diagnosis, demographics, and clinical features relevant to research uses. 2) Cell Isolation[unreadable] and Culture- Isolate primary and passaged primary epithelial cells for distribution to project investigators.[unreadable] Maintain stocks of frozen cells and prepare media and substrates to support preparation of well-differentiated[unreadable] airway epithelial cultures as dictated by investigator needs. 3) Genetic Mainipulation of Cell Cultures-[unreadable] Provide support for adenoviral and retroviral expression of molecules under study by project investigators.[unreadable] Through these functions, and in conjunction with other Cores in this application, the Cell Culture Core will[unreadable] support research to better understand mechanisms underlying normal airway surface liquid homeostatsis,[unreadable] which is essential for healthy lungs.